Low vaccum - Can't find the leak - Anybody have advice?

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09-25-2008, 07:25 AM

#21

ezstriper

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think you are right there on the valves but you could try just loosning them at idle see if it changes, can't leave them loose but just a test, if not think you need to pull the timing cover

09-26-2008, 07:38 PM

#22

tbanzer

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Quote:

Originally Posted by GNJ

Thanks Tbanzer - The rockers on this motor are non-adjustable. If 0.020 was taken off the block then I think the push rods would be 0.020 farther into the lifter. The tight valve theory makes sense, but how do we explain that the compression is good on all 6 cylinders? If the valves were too tight wouldn't compression readings be low? Can you tell me more of what your thinking?

Pull A valve cover and check lifter preload. Set one of the cylinders to TDC compression stroke, lightly tighten rocker arms till the pushrod has all play taken up. Then see how many turns are neede to finish tightenening the rocker.

09-29-2008, 07:49 AM

#23

Airpacker

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Quote:

Originally Posted by ezstriper

the pressure you saw is normal..not sure a vacume leak would overcome the normal crankcase pressure, do you have another carb you can try ? also if the timing gear is off by a tooth that will cause the low vacume as well..

Oh yes t will. A leaking intake gasket will pull several inches of vacum on the crankcase at idle.

I think your chain might be one tooth out as well.

those are pretty stout compression numbers.